First measurement of anti-kT jet spectra and jet substructure using the archived ALEPH e+e- data at 91.2 GeV

Aug 16, 2022, 9:00 AM
Auditorium VMP8 (University of Hamburg)

Auditorium VMP8

University of Hamburg

Von-Melle-Park 8 20146 Hamburg Germany
Online presentation QCD


Yi Chen (Massachusetts Inst. of Technology (US))


We present the first anti-kT jet spectrum and substructure measurements using the archived ALEPH e+e- data taken in 1994 at a center of mass energy of sqrt(s) = 91.2 GeV. Jets are reconstructed with the anti-kT algorithm with a resolution parameter of 0.4. It is the cleanest test of jets and QCD without the complication of hadronic initial states. The fixed center-of-mass energy also allows the first direct test of pQCD calculation. We present both the inclusive jet energy spectrum and the leading dijet energy spectra, together with a number of substructure observables. They are compared to predictions from PYTHIA6, PYTHIA8, Sherpa, HERWIG, VINCIA, and PYQUEN. None of the models fully reproduce the data. The data are also compared to two perturbative QCD calculations at NLO and with NLL’+R resummation. The results can also serve as reference measurements to compare to results from hadronic colliders. Future directions, including testing jet clustering algorithms designed for future electron-ion collider experiments, will also be discussed.

Primary authors

Austin Alan Baty (Rice University (US)) Yi Chen (Massachusetts Inst. of Technology (US)) Christopher Mcginn (Massachusetts Inst. of Technology (US)) Dennis Perepelitsa (University of Colorado Boulder) Jesse Thaler (MIT) Marcello Maggi (Universita e INFN, Bari (IT)) Paoti Chang (National Taiwan University) Paoti Chang (National Taiwan University (TW)) Tzu-An Sheng (Massachusetts Institute of Technology) Tzu-An Sheng (Massachusetts Inst. of Technology (US)) Yang-Ting Chien Yang-Ting Chien (Georgia State University) Yen-Jie Lee (Massachusetts Institute of Technology) Yen-Jie Lee (Massachusetts Inst. of Technology (US))

Presentation materials